Floor care machines, such as floor polishing machines, having a rotatably drivable floor care disc are known in the art. Such a conventional floor care machine typically has a machine frame or chassis carrying a drive motor and a drive arrangement that couples the drive motor to the floor care disc, so as to rotationally drive the floor care disc about a vertical rotation axis. The known floor care machine also includes guide and support elements such as rollers or wheels that support the machine on the floor in a movable or rollable manner. It is also known to construct the drive arrangement so that it permits a height adjustment of the floor care disc relative to the floor and relative to the guide wheels or rollers, so as to adjust the contact pressure or pressing force of the floor care disc on the floor.
A conventional floor care machine of the above described general type is known from the German Patent Publication DE 198 57 628 and the counterpart U.S. Pat. No. 6,308,360, the entire disclosure of which is incorporated herein by reference. Such a known floor care machine has a drive arrangement that enables the height of the floor care disc or pad relative to the floor surface to be adjusted automatically depending on the floor characteristics, in order to avoid damaging the floor surface. The height adjustment is carried out automatically dependent on the applied drive torque. Thus, the torque regulating height adjustment also ensures a continuous operation without overloading the drive. While the known machine according to the above mentioned patents is effective for its intended objects and purposes, it is desired to still further improve the adjustable drive arrangement in terms of a robust durable mechanism that has low maintenance and repair requirements for a long operating life, even in heavy duty commercial applications for such floor care machines. Particularly, it has been found that either the transmission elements of the height adjustable drive arrangement necessary for an automatic height adjustment are not durable or robust enough, or it is difficult to construct the adjusting mechanism in such a manner to achieve a wear-free embodiment with a simple assembly and durable operation. Thus, the present invention further develops and improves the drive arrangement known from the above mentioned patents, the entire disclosures of which are incorporated herein by reference. The present application will further disclose certain modifications, replacements, and additions to the components and features disclosed in the prior patents.